JP2010515406A - Method and apparatus for discharging an energy storage system for electrical energy - Google Patents

Abstract

The present invention relates to an energy storage system (2), in particular a vehicle having a hybrid drive train, during the discharge of the energy storage system (2), in particular a first discharge supplied with a coolant (14) which is carbon dioxide. With respect to a method and apparatus for removing heat by discharging with a resistor (12), the hybrid vehicle likewise includes such an apparatus.
[Selection] Figure 1

Description

  The present invention relates to a method and apparatus for discharging an energy storage system for electrical energy using a discharge resistor, particularly in an automobile having a hybrid power transmission path (hereinafter referred to as “hybrid vehicle”), and a hybrid vehicle including such an apparatus. About.

  Hereinafter, the present invention will be described in relation to a hybrid vehicle. However, the present invention is not limited to this application. For example, the present invention can be applied to a stationary power generation system equipped with such an energy storage system. The present invention is further applicable to stationary and / or mobile construction equipment or off-road machines such as construction vehicles.

  Hybrid vehicles generally have at least two drive engines, and most often a conventional internal combustion engine is facilitated by an additional electric drive unit. The electrical energy that operates the electric drive unit is typically supplied from an energy storage system that stores the electrical energy generated by the fuel cell or generator, such as a high voltage capacitor or battery.

  If a hybrid vehicle is involved in an accident, etc., the high voltage energy stored in the energy storage system can pose a danger to the rescue team or other assistants or the passengers themselves. Therefore, in such situations, it is necessary to discharge the energy storage system as early as possible.

  In general, the discharge of the high-pressure energy storage system is preferably performed by a discharge resistor. The discharge resistor limits the discharge current and prevents explosion or uncontrolled dangerous behavior of the energy storage system during or after the discharge process. The resistance value of the discharge resistor is selected to be large enough to control the discharge process and discharge it without damaging the energy storage system.

  Another discharge process is disclosed in Patent Document 1, in which two discharge methods (discharge using a general discharge resistor and corona discharge) are performed in parallel. The discharge process itself begins in the event of an accident.

  Unfortunately, applying a high resistance value to the discharge resistor or applying the two discharge methods described above will take several minutes to complete the discharge process (even if they are done in parallel). It will be. Meanwhile, rescue operations cannot be performed safely, and human life may be sacrificed.

JP 2004-129367 A

  Accordingly, it is an object of the present invention to provide a method and apparatus for discharging an energy storage system for electrical energy that reduces the time required to discharge the energy storage system. It is another object of the present invention to provide a method and apparatus that reduces the risk of facing the risk of secondary damage from the discharge process.

  The above object is achieved by a method and apparatus for discharging an energy storage system for electrical energy as defined in claims 1 and 22 and a hybrid vehicle carrying the apparatus according to claim 50 in the appended claims. The

  The present invention is based on the conclusion that the heat generated during the discharge process is one of the main factors limiting the use of resistors with very low resistance values during the discharge of energy storage systems. Thus, according to the present invention, a coolant that removes heat generated during the discharge process is supplied to the resistor during the discharge process. It is advantageous to manufacture the discharge resistor from an alloy having a positive temperature coefficient, such as Kanthal, Constantan, Tungsten.

  The use of carbon dioxide as a coolant has the advantage of being useful as a fire extinguishing material in addition to being fairly inexpensive. The coolant could also be used to extinguish fires and prevent such fires when resistors and / or energy storage systems are burned by heat generated by rapid discharge. Thus, in a preferred embodiment of the present invention, coolant is also supplied to the energy storage system itself.

  Furthermore, in a preferred embodiment, the coolant is stored in a pressurized state in a pressurized storage unit. When the coolant is discharged, the temperature of the storage unit drops rapidly. The energy storage system and / or the discharge resistor can be further cooled by the rapid temperature drop. By incorporating the storage unit into the energy storage system and / or the discharge resistor, this effect can be exploited to the fullest. In addition, the incorporation of a storage unit has the additional advantage that the size of the device can be reduced.

  Another advantageous embodiment uses at least one energy consuming device connected to the energy storage system to discharge the energy storage system and / or to assist the discharge process. When it is necessary to discharge the vehicle energy storage system, it is preferable to use an electric engine to discharge the energy storage system.

  In another preferred embodiment, the discharge process starts based on a trigger signal. The trigger signal can be automatically transmitted from, for example, a vehicle and / or manually transmitted by, for example, a rescue team by remote control.

  Preferably, the trigger signal is transmitted by a system such as an accident detection sensor or a collision prevention detection system. Accident detection sensor or accident detection system recognizes the moment when an accident occurs and can measure the possibility of an accident, even if it is a sensor that relates the start of the discharge process to an airbag deployment signal, for example It may be an accident prediction sensor that transmits a trigger signal when the characteristic exceeds a certain threshold. Both of these solutions have the main advantage that, when the rescue team arrives, they are already discharging, or if the accident prediction sensor or system is used, the discharging is already complete or nearly complete. .

  Signaling the state of the discharge process, i.e. providing a signal that the discharge of the energy storage system has already been completed or is still in progress and / or that a discharge needs to be started and carried out from now on This is further advantageous.

  Further advantages and preferred embodiments of the invention will become apparent from the dependent claims, the accompanying drawings and the following description.

  Hereinafter, the present invention will be described in more detail with reference to the drawings. The disclosed embodiments are merely exemplary and are not intended to limit the scope of the claims of the invention.

1 is a schematic diagram illustrating a first preferred embodiment of an apparatus for discharging an energy storage system according to the present invention. FIG. 4 is a schematic diagram illustrating a second preferred embodiment of an apparatus for discharging an energy storage system according to the present invention.

  FIG. 1 schematically shows a first preferred embodiment of the device according to the invention. The energy storage system 2 stores electrical energy generated by a fuel cell or generator (not shown) and is designed for high voltage. Such high voltage energy storage systems typically store energy on the order of hundreds of volts, unlike “normal” vehicle batteries that provide electrical energy at voltage levels of 12V or 24V. The energy storage system 2 can comprise a capacitor or battery connected in series with a negative electrode 4 and a positive electrode 6. In FIG. 1, only a single capacitor or battery is shown for simplicity of illustration.

  Since the energy storage system 2 has a high voltage system, in the event of an accident, it may pose a danger to rescue teams or other assistance personnel or vehicle occupants. Therefore, in such a situation, it is necessary to discharge the energy storage system 2 to zero or a safe level as early as possible.

  In order to discharge the energy storage system 2, the negative electrode 4 and the positive electrode 6 of the energy storage system 2 are connected to the first electric circuit 8 having the first switch 10. As soon as the first switch 10 is closed, the discharge process is started by closing the electrical circuit 8. In order to control the discharge and prevent damage to the energy storage system 2, the first electrical circuit 8 includes a first discharge resistor 12 that limits the discharge current I.

  In yet another embodiment, existing energy consuming equipment can be used as a discharge resistor to aid the discharge process by discharging or consuming as much energy as possible. For example, if the vehicle energy storage system is to be discharged as early as possible, it is advantageous to consume as much energy as possible using the electric engine of the vehicle. Since this discharge process may take too long, energy consuming equipment can also be used only to assist the discharge process. The less energy stored, the faster the discharge process.

  The first discharge resistor 12 is, for example, a winding resistor having a relatively low resistance value and a positive temperature coefficient. Here, “low” refers to the highest discharge current in a range in which the energy storage system 2 cannot be in danger such as battery explosion. This further means that if the resistance is “too low”, adverse conditions may arise due to the discharge itself, such as battery explosion, capacitor combustion or generation of harmful gases. Therefore, the discharge current must be adapted to each battery and capacitor used in the system. If the resistance value is “too high”, the discharge process will be too slow. Therefore, it is preferable to use the resistor 12 whose resistance value is temperature-dependent. This means that the resistance value is relatively low when the resistor 12 is at a low temperature, but the resistance value increases as the temperature increases.

  Such resistors are manufactured from, for example, Kanthal, Constantan, tungsten windings. The energy storage system 2 can be discharged very quickly, preferably within a few seconds, like the resistors known from the prior art, due to the relatively low resistance value. Unfortunately, the relatively rapid discharge process generates a large amount of heat even when using resistors with a positive temperature coefficient. The heat of discharge entails a risk of burning throughout the system, and thus a fire and / or explosion hazard.

In order to enable a very rapid discharge while reducing the possibility of combustion, the device of the invention is preferably stored in a coolant storage unit 16 such as a tank, preferably carbon dioxide (Co ₂₎ stored under pressure. ) Or the like. Due to the discharge of the coolant, the temperature of the storage unit rapidly decreases. Due to the rapid temperature drop, the energy storage system and / or the discharge resistor can be further cooled.

  Since the storage unit itself provides a cooling source, the storage unit 16 may be an integral part of the energy storage system 2 and / or the discharge resistor 12 when coolant is released. This has the further advantage that no coolant loss can occur due to the long transfer path. However, simply by incorporating the coolant storage unit into the energy storage system and cooling the energy storage system using the temperature drop due to the injection of coolant into the discharge resistor, the coolant can be used to cool the discharge resistor. Or vice versa.

  In any case, the use of carbon dioxide provides the added advantage that carbon dioxide also serves as a fire extinguishing material when the system burns. Basically, a non-conductive gas or liquid, such as an inert gas, which is suitable and fire resistant as a coolant may be used.

  When the first switch 10 is closed and the discharge process begins, the coolant 14 is sent to the first discharge resistor 12. This is indicated by arrow 18 in FIG. In order to cool the first discharge resistor 12 optimally, the first discharge resistor 12 is provided with a plurality of cooling holes 20 so that the coolant (or simply air) can be supplied to the first discharge resistor 12. The resistor winding can be cooled.

The coolant 14 is sent to the first discharge resistor 12 by providing means such as a guide groove (not shown). When the coolant 14 such as CO ₂ is stored in a pressurized state and is located in the vicinity of the first discharge resistor 12, when the pressure tank 16 is opened, the coolant is ejected from the opening of the tank 16. However, since this may be directed to the first discharge resistor 12, no special supply means as described above is required.

  More preferably, the coolant 14 is also sent to the energy storage system 2. If the discharge process is quick, the energy storage system 2 itself is affected by heat. Therefore, by cooling the energy storage system 2, a more rapid discharge process can be expected. The supply of coolant 14 to the energy storage system 2 is indicated by arrows 22. For the purposes described above, the coolant 14 is routed through the first discharge resistor 12 and then to the energy storage system 2, but the coolant flow is split to divide the first portion into the discharge resistor 12 and others. Can also be sent to the energy storage system 2. The amount of these flows may be the same, but supplies more coolant 14 to the first discharge resistor 12 and only the lesser coolant 14 to the energy storage system 2. May be sent or vice versa.

  It is also possible to place the first discharge resistor 12 in the vicinity of the energy storage system 2 or to incorporate the first discharge resistor 12 or a part thereof into the energy storage system 2. Thereby, it becomes easy to supply the coolant 14 to both the first discharge resistor 12 and the energy storage system 2.

  After cooling the first discharge resistor 12 and / or the energy storage system 2, the coolant 14 is released into the atmosphere. This is indicated by arrow 24.

  The first switch 10 is activated based on a trigger signal 26 emitted from a trigger signal source 28, thereby starting a discharge process. The first switch 10 is closed and the coolant storage unit 16 is opened based on the trigger signal, so that the coolant 14 is supplied to the first discharge resistor 12 and / or the energy storage system 2 during the discharge process.

  The trigger signal 26 is transmitted manually and / or automatically. If the signal is transmitted manually, the discharge process can be initiated by a person, for example a rescue team or crew, by pressing a button on the vehicle or remotely. Remote operation has the advantage of avoiding direct contact with the vehicle. Further, it is possible to send a signal indicating the necessity of discharge from the vehicle itself to the remote control device. This may be suitable when the automatic start of the discharge process fails or when it is desired to further control the start of the discharge process.

  In another preferred embodiment, the trigger signal is automatically transmitted. For example, the trigger signal is transmitted by an accident detection system or sensor. The accident detection system or sensor senses the occurrence of an accident and then sends a trigger signal. Since the same principle applies to airbag deployment, the trigger signal can also be associated with the airbag deployment signal.

  The accident detection system or sensor may be part of an accident prediction system. Using this accident prediction system, the possibility of an accident can be measured, and a trigger signal can be transmitted when the measured possibility of an accident exceeds a predetermined threshold. Preferably, the trigger signal is transmitted a predetermined time before the accident occurs, so that at the moment of the actual accident, the energy storage system is already (almost) completely discharged, or at least largely discharged. ing. By correlating the time required to discharge the energy storage system to a “safe” level or zero and the predetermined period of time described above, the energy left in the energy storage system is “predetermined” or this The energy storage system can be discharged to achieve a “safe” level. The main advantage of pre-initiating the discharge process prior to the actual accident is that immediately after the accident occurs, rescue teams or other personnel are at risk of being damaged by the energy stored in the energy storage system 2. It is possible to reach the vehicle without inconvenience and to rescue it.

  In another preferred embodiment, an information signal and / or a “safe” signal may be transmitted in addition to the trigger signal. An information signal can be transmitted, for example, to a rescue service center, an accident reporting center, an accident recorder, or generally outside the vehicle, indicating that the discharge process is in progress or still needs to be performed. The information signal is an acoustic or visual warning signal that warns people not to get close to the vehicle if the discharge process fails, the discharge process is still in progress, or still needs to be performed. Form may be sufficient.

  The “safety signal” means that there is no longer any danger in performing a rescue regardless of the presence of the vehicle energy storage system 2 due to the completion of the discharge process or because the energy storage system is not charged to a dangerous level. Communicate that people who came to the accident site may approach the vehicle.

  The trigger signal manual transmission and the automatic transmission may be combined so that the discharge can be started even when the automatic transmission fails due to vehicle damage.

  In addition to the first discharge resistor 12 and the first electrical circuit 8, a second (independent) comprising a second discharge resistor having a resistance value higher than the resistance value of the first discharge resistor 12. An electrical circuit may be provided, thereby providing a controlled discharge process that progresses more slowly than the discharge process controlled by the first discharge resistor 12. Instead of using two different discharge resistors provided in two different electrical circuits, it is also possible to use a single discharge resistor whose resistance value can be adjusted.

  FIG. 2 shows a second embodiment of the device according to the invention. FIG. 2 shows the same components as in FIG. 1, but additionally shows a second electrical circuit 30 comprising a second discharge resistor 32 and a second switch 34. Basically, a single three-position switch that closes either the first electrical circuit 8 or the second electrical circuit 30 (instead of the two switches 10 and 34 in FIG. 2) can also be used.

  The second switch 34 of FIG. 2 is also activated by a trigger signal 26 generated by a trigger signal source. As shown in FIG. 2, the trigger source may be the same as the trigger signal source 28 that transmits the trigger signal 26 to the first switch 10.

  Unlike the discharge process performed by the first electrical circuit 8 having the first discharge resistor 12, the discharge process performed by the second discharge circuit 30 and the second discharge resistor 32 is the second discharge resistance. Since the resistance value of the device 32 is low, it is considerably slow. Therefore, the discharge process using the second discharge resistor 32 is not performed in an emergency, and is performed in all cases other than “emergency” where the energy storage system 2 needs to be discharged, such as maintenance, repair or simple parking. Is done. Thus, in this case, the trigger signal 26 is not correlated or associated with an accident related system such as the accident detection sensor described above.

  The trigger signal 26 for the second switch 34 is manually transmitted by a driver or repairman pressing a corresponding button provided on the vehicle or remotely. In principle, the trigger signal 26 can also be generated automatically. This can be done, for example, by associating the trigger signal 26 with a GPS signal indicating the location of the garage (or any other maintenance location) or by associating the transmission of the trigger signal 26 with the operation of the vehicle's central locking system. Can do.

  The discharge process made possible by closing the second electrical circuit 30 “runs more slowly” provides the advantage of further reducing the risk of secondary damage from the discharge process.

  Preferably, an existing energy consuming device, in particular a vehicle engine, is used as the second discharge resistor 32. Discharging by energy consuming equipment is a slower and slower process, thus ensuring that the energy storage system is not damaged.

DESCRIPTION OF SYMBOLS 2 Energy storage system 4 Negative electrode 6 Positive electrode 8 1st electric circuit 10 1st switch 12 1st discharge resistor 14 Coolant 16 Coolant storage unit 18 Flow of coolant to discharge resistor 20 Cooling hole 22 Energy storage Coolant flow to system 24 Coolant flow to atmosphere 26 Trigger signal 28 Trigger signal source 30 Second electrical circuit 32 Second discharge resistor 34 Second switch

Claims (50)

A method of discharging an electrical energy storage system (2) using a first discharge resistor (12), comprising:
Storing the pressurized coolant (14) in a storage unit (16);
During the discharge of the energy storage system (2), the storage unit is opened to inject the coolant and supply the coolant (14) to the first discharge resistor (12), thereby generating heat. And removing.   The method of claim 1, wherein the coolant (14) is also supplied to the energy storage system (2).   The method according to claim 1 or 2, wherein the coolant (14) is carbon dioxide.   The method according to any of the preceding claims, further comprising the step of initiating discharge of the energy storage system (2) based on a trigger signal (26).   The method of claim 4, wherein the trigger signal (26) is transmitted by a manually operable signal transmitter.   The method according to claim 4 or 5, wherein the trigger signal (26) is transmitted by remote control.   The method according to any one of claims 4 to 6, wherein the trigger signal (26) is automatically transmitted by an accident detection sensor.   The accident detection sensor is part of an accident prediction system that senses the likelihood of an accident and transmits the trigger signal (26) if the probability of the accident exceeds a predetermined accident probability threshold. Item 8. The method according to Item 7.   The method according to any one of claims 4 to 8, wherein the trigger signal (26) is correlated with an airbag deployment signal.   The method according to any one of claims 7 to 9, wherein the trigger signal (26) is transmitted a predetermined period before the occurrence of an accident detected by an accident detection sensor.   The method according to claim 10, wherein the predetermined period is correlated with the time required to discharge the energy storage system (2) to a predetermined level.   The method according to claim 1, further comprising transmitting an information signal when the discharge starts.   13. The method according to claim 12, wherein the information signal is transmitted to a rescue service center and / or an accident reporting center and / or an accident recorder.   The method further comprises the step of transmitting a safety signal when the time required to discharge the energy storage system (2) to a predetermined level and / or to discharge the energy storage system (2) to a predetermined level has elapsed. 14. The method according to any one of 13 to 13.   15. A method according to claim 11 or 14, wherein the predetermined level is 75V or less for DC or 60V or less for AC.   Method according to any of the preceding claims, wherein the discharge resistor (12) is made from a metal alloy having a positive temperature coefficient, preferably Kanthal, Constantan and / or Tungsten.   17. A method according to any of the preceding claims, wherein at least one energy consuming device is used as a discharge resistor (12; 32) and / or to assist discharge due to energy consumption.   The method according to any of the preceding claims, wherein the energy storage system (2) comprises at least one capacitor and / or at least one battery.   The method according to any of the preceding claims, wherein the coolant is stored in the energy storage system (2) and / or the discharge resistor (12).   20. A method according to any preceding claim, wherein the method is performed only in an emergency. In all other cases, especially during maintenance or repair or during parking, use a second discharge resistor (32) or appropriate energy consuming equipment,
The resistance value of the second discharge resistor (34) is longer than the discharge of the energy storage system (2) using the first discharge resistor (12) in the time required for the energy storage system (2). 21. The method of claim 20, wherein the method is adapted to perform a discharge. Discharging an electrical energy storage system (2) comprising an energy storage system (2) and a first discharge resistor (12) connected to the energy storage system (2) via a first connector (10) A device for causing
Further comprising at least one storage unit (16) for storing the pressurized coolant (14);
When the storage unit (16) is opened, coolant is injected, thereby supplying the coolant (14) to the first discharge resistor (12) during discharge of the energy storage system (2), and heat. The apparatus characterized by removing.   23. Apparatus according to claim 22, wherein the coolant (14) is also supplied to the energy storage system (2).   24. Apparatus according to claim 22 or 23, wherein the coolant (14) is carbon dioxide.   25. Apparatus according to any one of claims 22 to 24, wherein the storage unit (16) is integrated into the energy storage system (2) and / or the discharge resistor (12).   26. The coolant according to any one of claims 22 to 25, wherein the coolant (14) is supplied to the first discharge resistor (12) and / or the energy storage system (2) through at least one induction groove. Equipment. The first discharge resistor (12) has a plurality of resistance windings;
27. Any one of claims 22 to 26, wherein the first discharge resistor (12) is provided with a plurality of holes (20) for introducing the coolant (14) into the resistance winding. The device according to item.   28. Apparatus according to any one of claims 22 to 27, wherein the first discharge resistor (12) is manufactured from a metal alloy having a positive temperature coefficient, preferably Kanthal, Constantan and / or Tungsten.   29. Apparatus according to any one of claims 22 to 28, wherein the first discharge resistor (12) is a component integrated with the energy storage system (2).   30. Apparatus according to any one of claims 22 to 29, wherein the first discharge resistor (12) is at least one energy consuming device.   31. The apparatus according to any one of claims 22 to 30, further comprising at least one energy consuming device connected to the energy storage system (2) and usable for discharging the energy storage system (2). Equipment.   32. Apparatus according to any one of claims 22 to 31, wherein the first connector (10) is a superconductor made from a material such as an electrical switch, relay or solenoid, or silicon carbide (SiC). .   33. Apparatus according to any one of claims 22 to 32, wherein the energy storage system (2) comprises at least one capacitor and / or one battery.   34. Apparatus according to any one of claims 22 to 33, further comprising a trigger signal transmitter (28) for transmitting a trigger signal (26) for initiating discharge of the energy storage system (2).   35. Apparatus according to claim 34, wherein the trigger signal transmitter (28) is a manually operable signal transmitter.   36. Apparatus according to claim 34 or 35, wherein the trigger signal transmitter (28) is a remote controlled transmitter.   37. Apparatus according to any one of claims 34 to 36, further comprising an accident detection sensor designed to automatically transmit the trigger signal (26).   The accident detection sensor is designed to sense the possibility of an accident and to send the trigger signal (26) if the possibility of the accident exceeds a predetermined accident probability threshold. 37. Apparatus according to 37.   38. Apparatus according to any one of claims 34 to 37, wherein the trigger signal (26) is correlated with an airbag deployment signal.   40. Apparatus according to any one of claims 34 to 39, wherein the trigger signal (26) is transmitted a predetermined time period before the occurrence of an accident detected by an accident detection sensor.   41. The apparatus according to claim 40, wherein the predetermined period is correlated with the time required to discharge the energy storage system (2) to a predetermined level.   42. The apparatus according to any one of claims 22 to 41, further comprising an information signal transmitter for transmitting an information signal when the discharge starts.   43. The apparatus of claim 42, wherein the information signal is transmitted to a rescue service center and / or an accident reporting center and / or an accident recorder.   Further comprising a safety signal transmitter for discharging the energy storage system (2) to a predetermined level and / or transmitting a safety signal when a time required for discharging the energy storage system (2) to a predetermined level has elapsed. 44. Apparatus according to any one of claims 22 to 43.   45. An apparatus according to claim 41 or 44, wherein the predetermined level is 75V or less for DC or 60V or less for AC.   46. The trigger signal transmitter (28) and / or the information signal transmitter and / or the safety signal transmitter are implemented as a single signal transmitter capable of transmitting a plurality of different signals. The apparatus as described in any one of.   47. Apparatus according to any one of claims 22 to 46, wherein the first discharge resistor (12) is used only in an emergency. A second discharge resistor (32) is connectable to the energy storage system (2) via a second connector (34);
The second discharge resistor (32) is used in all cases except for an emergency, and the resistance value of the second discharge resistor (32) uses the first discharge resistor (12). 48. Apparatus according to claim 47, adapted to discharge the energy storage system (2) in a longer time than the discharge of the energy storage system (2).   49. The apparatus of claim 48, wherein the second discharge resistor (32) is at least one energy consuming device.   A vehicle equipped with a device for discharging the electrical energy storage system (2) according to any one of claims 22 to 49, preferably a vehicle having a hybrid power transmission path.

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